Tape tension clamp for slide fastener machines



Sept. 26, 1950 A. e. NATZKE 2,523,337

TAPE TENSION CLAMP FOR SLIDE FAS'I'ENER MACHINES Filed Oct. 8, 1945 2 Sheets-Sheet 1 INVENYUK z ATTORNE Y Sept. 26, 1950 A. G. NATZKE 2,523,387

.TAPE TENSION CLAMP FOR SLIDE FASTENER MACHINES Filed Oct. 8, 1945 2 Sheets-Sheet 2 2 5 1.2V VLlNTOR E ATTO RN E v Patented Sept. 26, 1950 2,523,387 ICE TAPE TENSION CLAMP FOR SLIDE FASTENER MACHINES Alfred G. Natzke, Lynbrook, N. Y., assignor to Lamar Slide Fastener Corp., New York, N. Y., a corporation of New York Application October 8, 1945, Serial No. 620,866

4 Claims.

This invention rel-ates to machines for making slide fasteners and more particularly to the means provided in such machines for driving the flexible material to'which the fastener elements are attached in the operation of the machines.

In the manufacture of slide fasteners, the fastener elements or scoops are clamped in succession upon a beaded tape or the like, which is fed to a machine wherein it is given an intermittent or step-by-step movement in predetermined time relation to the feeding of the scoops, these latter being either separately produced, hoppered and individually conveyed to the tape, or finished in the same machine wherein their clamping to the tape is effected according to various methods, for instance from interconnected series of embryo scoops. In all cases it is essential that the tape be properly tensioned and its movement accurately controlled in order to secure the exact spacing between successive scoops required for the smooth operation of the slide fastener, or to provide gaps of predetermined length between series of scoops defining fastener stringers and obtained through the continued movement of the tape while the feeding of the scoops thereto is interrupted.

A commonly used type of mechanism for driving the tape comprises a tape feed drum suitably rotated in synchronism with the scoop feeding and clamping means and usually having aknurled periphery for frictional engagement of the surface of the tape, and a tape holding and tensioning device associated with the drum which consists of a spring pressed shoe adapted to hold the tape against the drum periphery, whereby to insure constant driving engagement of the tape b the drum and maintain the tape sufficiently taut.

It is well known to those skilled in the art that such mechanisms are not entirely satisfactory and do not always insure such an accurate spacing of the scoops as might be desired, chiefly because the relatively high pressure applied bythe stationary shoe on the tape and required to prevent sliding of the tape relative to the drum results, at a high speed of operation of the machine, in an objectionable friction and strain on the tape and often causes a slight pinching or foldin of the tape, the cumulative eifect whereof is sufficient to produce uneven advancement of the tape and spacing of the scoops.

It is therefore the primary object of the invention to provide a novel and improved tape tensioning and holding device associated with a tape driving drum which, while effective to hold the tape against the drum periphery and positively to prevent lost motion, thereby insuring uniform spacing of the scoops at any time, eliminates any objectionable friction on the tape and the shortcomings caused thereby.

Another object is to provide means, as aforesaid, which are of simple construction, reliable in operation, applicable to slide fastener machines employing the usual tape feed drum without changing the structure of such machines, and subject to a minimum of wear.

A further and more specific object is to provide a device for holding the tape against the driving drum wherein the usual friction shoe is dispensed with and the holding action is effected through pressure exerting means maintained in rolling engagement with the tape during the advancement of this latter.

These and other objects will become apparent in the following description of the invention illustrated in the drawings wherein:

Fig. l is a perspective view of a portion of a machine for making slide fasteners incorporating a device according to the invention.

Fig. 2 is an enlarged side elevation of the device of Fig. 1, shown in operative position.

Fig. 3 is a longitudinal section of the device shown in retracted or inoperative position.

Fig. 4 is a top plan View of the device, partly in horizontal section on line 4 i of Fig. 2.

Referring now in detail to the drawings, H) indicates a conventional tape feed drum fastened to ashaft suitably journalled in stationary element II or portion of the frame of the machine, the shaft being driven with a step by step motion in predetermined time relation to the scoop feeding and clamping means of the machine through suitable kinematic connections not shown. The periphery of the drum in is preferably knurled, as at H, and the tape I3 is frictionally engaged by said knurled surface to be driven thereby.

A bracket l4, suitably fastened to the stationary element I I aforesaid in proximity of the drum l0, slidably carries at its free end a shaft l5 which is radially alined with the drum and has fast there-- on, at its rear end, a collar l6 provided with radially extending grooves l'l best shown in Fig. 3.

Freely mounted on the shaft l5 between the collar i6 and the free end of the bracket, is a further collar l8 carrying a lever [9' and provided with cam projections 20 profiled to fit the grooves I1 and normally received therein, the rotation of said collar l8 being effective to disengage the cams 20 from the grooves ll and longitudinally to displace the shaft iii in a rearward direction for the purpose hereinafter set forth.

The forward end of the shaft i5 is provided with an integral fork 2i and a fiange 22, a coil spring 23 being, mounted on the shaft between said flange and the Iree end of the bracket M to urge the shaft IS in a forward direction toward the drum H). An elongated member or yoke 24 comprises parallel plates 25 that are centrally united by an integral portion of the member formed with a projecting tongue 26 (see Figs. 3 and 4) which is adapted to be received within the fork 2| and is mounted therein by means of a pin 21 so as to pivotally connect the member 24 to the shaft [5. The front portion of the plates 25 is centrally undercut to define an arcuate surface 28, the radius whereof is substantially equal to the radius of the drum it.

Mounted between the plates 25 at their opposite ends, are two rollers 29 rotatably carried by pins 30 secured to the plates, the rollers preferperiphery of the drum and thereby caused to' move with the drum in th intermittent motion of this latter, while being maintained sufficiently taut in correct relation to other elements of the machine. The pressure is exerted by the rollers on the'tape at considerably spaced points along the periphery of the drum and is sufificient positively to prevent any lost motion.

On the other hand, due to the fact that the pressure exerting rollers are obviously caused to rotate during the movement of the tape which they engage, this latter is not subject to any objectionable friction and any tendency of the tape to form folds is entirely eliminated. The pivotal [connection of the roller-supporting member 24 like, with the consequent 'even pressure on the tape and smooth action of the device.

To render the mechanism inoperative whenever desired for changing the tape or any other reason, it is manifestly sufficient manually to operate the lever l9 to displace the shaft I rearwardly as aforementioned, so as to withdraw the rollers from the drum and release the tape.

It will be understood that changes and modifications may be made in the structures described and illustrated in the drawings, without departing from the spirit of the invention or. exceeding the scope of the claims.

I claim:

1. In a machine for making slide fasteners comprising a rotatable drum for feeding a tape for mounting fastener scoops, ,a bifurcated member slidably movable toward and away from said drum, a support member adjacent said drum and pivotally mounted on said movable member within the bifurcation thereof, a stop at the end of said movable member distant from said bifurcation thereof, a pair of spaced knurled rollers carried by said support member, adapted to engage the tape' on the drum at spaced points, means for normally urging said movable-member toward the drum to maintain said rollers in pressure-exerting engagement with the tape and the tape in engagement with the drum at the points of contact 'of the rollers, and means operable againstsaid stop to longitudinally displace the same and to move the movable member and therefore the support member against said spring away from the drum to release the tape.

2. In a machine for making slide fasteners comprising a rotatable drum for feeding a tape for mounting fastener scoops, a bracket, a shaft slidably carried by said bracket, abifurcation at one end of said shaft and a fixed collar at the other end thereof, an elongated member pivotally connected, centrally thereof in the bifurcation of said shaft and extending adjacent the periphery ofsaid d'rum, a 'pair of spaced rollers mounted at the opposite ends of said elongated member equidistant from the pivoted connection thereof,

spring means associated with the shaft and the bracket for urging the shaft toward the periphery of the drum to press said rollers into contact with a tape on said periphery and hold the tape in driven engagement with the drum, and cam means rotatably actuable for displacing the collar, and therefore, the shaft away from the drum to withdraw the rollers from the tape.

3. In a machine for making slide fasteners comprising a rotatable drum for feeding a' tape. for mounting fastener scoops, a bracket, a, shaft slidably carried bysaid bracket, an elongated member pivotally connected centrally thereof to one end of saidshaft and extending adjacent the periphery of said drum, a pair of spaced rollers mounted at the opposite ends of said elongated member, spring means associated with the shaft and the bracket for urging the shaft toward the periphery of the drum to press said rollers into contact with a tape on said periphery and hold th tape in driven engagement with the drum, and manually operable cam means acting longitudinally against said shaft fordispl'acing the shaft away from the drum to withdraw the rollers from the tape.

4. In a machine for making slide fasteners comprising a rotatable drum for feeding a tape for mounting fastener scoops, a bracket, a shaft slidably' carried by said bracket, an elongated member pivotally connected centrally thereof to one end of said shaft and extending adjacent theperiphery of said drum, a pair of spaced Number Name Date 1,120,770 Wagner et a1 Dec. 15, 1914 1,185,260 Stine May 30, 1916 1,936,940 Johnson .Nov. 28, 1933 1,972,555 Fear Sept- 4, 1934, 2,119,670 Fitzgerald June 7, 1938 2,123,488 Presby July 12, 1938 2,134,998 Cavalcante Nov. 1, 1938 2,199,270 Roselius et al Apr. 30, 1940 FOREIGN PATENTS Number Country e Date 708,112 France Apr. 27, 1931 726,093 France Feb. 23, 1932 rollers mounted at the opposite ends of said elongated member, spring means associated with the shaft and the bracket. for urging the shaft toward the periphery of the drum to press said rollers into contact with a tape on said periphery and hold the tape in driven engagement with the drum, a collar rigidly carried by said shaft near the other end thereof, a sleeve member rotatable with respect to said shaft and interposed between said collar and said bracket, cooperating cam and cam groove means provided in the adjacent portions of said collar and sleeve member, whereby when said cam and cam groovemeans are in engagement said spring means are allowed to maintain the shaft in a position wherein said rollers are in pressure engagement with the tape, and means for manually rotating said sleeve member to bring said cam and cam groove means out of engagement with one another and thereby to displace the shaft away from the drum to withdraw the rollers from the tape.

ALFRED G. NATZKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

